Using JSX and React #React #reactjs #javascript #Framework #programming

Using JSX and React  #React #reactjs #javascript #Framework #programming

  • You use JSX within React code to easily create components for your apps.
  • Here is an example of JSX being used to render HTML:

    To create a component, just use a local variable that starts with an upper-case letter, e.g.:

    Note: There are reserved words in JSX, as it is essentially JavaScript after all—so keywords such as and are discouraged as attribute names.

  • Form creation is easy with JSX and sub-components, for example:

    To make this work, you must create the sub-components as attributes of the main component:

    To use some JavaScript to create a result for use in an attribute value, React just needs you to wrap it in curly braces like so:

    You can also just pass a boolean value for form attributes such as , and so on.

  • First we use to establish signalling of a new user connected via the as so:

    Then, to connect to the PeerServer, we use the following:

    We then listen for events via the method:

    We also have our JSX inside components in the directory.

  • Now it’s as simple as pushing your code to heroku:

    Once the push is finished, you will be able to start your web service with the following:

    Now just visit the URL provided, or as a shortcut use the command as so:

    You’ve learned how to create JSX components and interface them with React, with a detailed example of the chat application.

What You’ll Be CreatingJSX is similar to a mix of XML and HTML. You use JSX within React code to easily create components for your apps. JSX transforms into JavaScript when React compiles the…

@K0YCHEV: Using JSX and React #React #reactjs #javascript #Framework #programming

JSX is similar to a mix of XML and HTML. You use JSX within React code to easily create components for your apps. JSX transforms into JavaScript when React compiles the code.

The beauty of React is that you can create reusable code and easily structure your app from a component-based mindset. Finally, the gap between mocking up wireframes of semantically formed ideas and implementing them has never been closer.

Here is an example of JSX being used to render HTML:

var div =

; ReactDOM.render(div, document.getElementById(‘example’));

To create a component, just use a local variable that starts with an upper-case letter, e.g.:

var MyComponent = React.createClass({/*…*/}); var myElement = ; ReactDOM.render(myElement, document.getElementById(‘example’));

, for example.

Specify children inside your JSX as so:

var User, Profile; // You write in JSX: var app = click ; // What will get outputted in JS: var app = React.createElement( User, {className:”vip-user”}, React.createElement(Profile, null, “click”) );

Use the Babel REPL to test out JSX.

Form creation is easy with JSX and sub-components, for example:

var Form = FormComponent; var App = (

);

To make this work, you must create the sub-components as attributes of the main component:

var FormComponent = React.createClass({ … }); FormComponent.Row = React.createClass({ … }); FormComponent.Label = React.createClass({ … }); FormComponent.Input = React.createClass({ … });

curly braces like so:

// You write in JSX: var myUser = ; // Will become this in JS: var myUser = React.createElement( User, {username: window.signedIn ? window.username : ”} );

and so on. These values can also be hardcoded if you like by just writing plain HTML.

// Make field required ; ; // Check by default ; // Enable a field

When you want to set multiple attributes, ensure you do this on declaration of your component and never after. Later declaration becomes a dangerous anti-pattern that means you could possibly not have the property data until much later in execution.

spread operator.

var props = {}; props.username = username; props.email = email; var userLogin = ; “` You can use these prop variables multiple times. If you need to override one of the properties, it can be done by appending it to the component after the `…` spread operator, for example: “`js var props = { username: ‘jimmyRiddle’ }; var userLogin = ; console.log(component.props.username); // ‘mickeyFinn’

multi-line style comments inside your JSX. For example:

var components = ( {/* child comment, put {} around */} );

There are a few things that can confuse some people with JSX, for example when adding attributes to native HTML elements that do not exist in the HTML specification.

prefix like so:

You may have seen the app Gitter. It’s a real-time web chat application that’s mainly aimed at developers. Many people are using it to discuss their projects on GitHub, due to its easy integration with GitHub and being able to create a channel for your repository.

modules for Node.

To give you a clear idea of the architecture of the application, here is a basic low-level UML diagram:

ChatServer receives signal messages with PeerJS, and each client will use it as a proxy for taking care of the NAT traversal.

{ “name”: “react-webrtc-chat”, “version”: “0.0.0”, “description”: “React WebRTC chat with Socket.io, BootStrap and PeerJS”, “main”: “app.js”, “scripts”: { “start-app”: “node app.js”, “start”: “npm run start-app” }, “keywords”: [ “webrtc”, “react” ], “license”: “MIT”, “dependencies”: { “express”: “~4.13.3”, “peer”: “~0.2.8”, “react”: “~0.12.2”, “react-dom”: “^0.14.1”, “socket.io”: “~1.0.6” }, “devDependencies”: { “babel-preset-react”: “^6.0.14”, “babelify”: “^7.1.0”, “browserify”: “^12.0.1” } }

are packages for using Twitter’s CSS framework to style our app.

and add the following:

{ “name”: “react-webrtc-chat”, “main”: “app.js”, “version”: “0.0.0”, “ignore”: [ “**/.*”, “node_modules”, “bower_components”, “public/lib”, “test”, “tests” ], “dependencies”: { “react”: “~0.12.2”, “jquery”: “~2.1.4”, “eventEmitter”: “~4.2.7”, “peerjs”: “~0.3.14”, “bootstrap”: “~3.3.5” } }

Client library for wrapping the WebRTC.

file:

{ “directory”: “src/lib” }

From here, just sit back and install your dependencies via:

. These contain the modules ready for use.

, etc. This will be the main entry point of your application.

, which will actually do the WebRTC chat part.

to specify our app’s events.

peer.on(‘connection’, function (id) { io.emit(events.CONNECT, id); console.log(‘# Connected’, id); });

event to specify when a user has connected to our app. This will be used by the states of our view components to update their displays in real time.

To do this, we need to create the Server for our peer-to-peer connections to proxy through.

and add the following:

object with all of its functions.

as so:

ChatServer.prototype.connect = function (username) { var self = this; this.setUsername(username); this.socket = io(); this.socket.on(‘connect’, function () { self.socket.on(events.CONNECT, function (userId) { if (userId === self.getUsername()) { return; } self._connectTo(userId); self.emit(events.CONNECT, userId); console.log(‘User connected’, userId); });

Then, to connect to the PeerServer, we use the following:

this.peer = new Peer(username, { host: location.hostname, port: 9000, path: ‘/chat’ });

method:

this.peer.on(‘open’, function (userId) { self.setUsername(userId); }); this.peer.on(‘connection’, function (conn) { self._registerPeer(conn.peer, conn); self.emit(events.CONNECT, conn.peer); });

component for now:

component.

and served via node express.

to take a look at the chat.

set up at the Heroku Dev Center.

available, log in and create a new project like so:

. Heroku also creates a git repo for this app.

Now it’s as simple as pushing your code to heroku:

$ git push heroku master

Once the push is finished, you will be able to start your web service with the following:

command as so:

$ heroku open

directory are working.

apps for the cloud!

Using JSX and React